Process for the preparation of metallic magnesium.



FFICE.

ROGER WILLIAM WALLACE AND EUGENE WASSMER, or LoNDoN, ENGLAND.

PROCESS FOR THE PREPARATION OF METALLIC MAGNESIUM.

No Drawing.

Specification of Letters Patent.

Application filed August 18, 1913. Serial No. 785,324.

Patented Nov. 18, 1913.

To all whom it may concern Be it known that we, ROGER WILLIAM WALLACE,'I6SlCllDg at 2 Harcourt Buildings, Temple, London, E. (1, England, and EU- einnn AssMEmof 4-2 Manor House, Marylebone Road, London, N. W., England, have invented a new or Improved Process for the Preparation of Metallic Magnesium, of which the following is a specification.

Our invention consists in the preparatlon of metallic magnesium by treating a mixture of chlorid and sulfid of the metal in an electrolytic bath.

In one way of carrying out our invention magnesium chlorid or carnallite artificial or natural is fused in "a suitable vessel acting as one of the electrodes of a closed electrolytic bath with a central electrode. A calculated quantity of magnesium sulfid is then added gradually to the fused salt (precaution being taken to prevent admission of atmospheric air) so as to satisfy the general meaning of the following formulae M o1 +3M s=4Mg+ aegis.

Or the sulfid and chlorid of the magnesium may be mixed and added together to the fused constituents of the electrolyte. The electric current is passed through the fused mass which at once gives ofi vapor of sulfur chlorid and-in some cases sulfur also. These vapors are allowed to pass into a vessel where the sulfur is condensed and the remaining vapors of sulfur chlorid are then allowed to pass into another vessel in which they are condensed.

The magnesium in the bath may be collected in any suitable manner such for example as :--(1) Drawing oil that part of the formed magnesium which is in a liquid state,

- or, if necessary or advantageous, (2) by introducing into the bath when tappin fiuorspar or any other suitable flux whic willcause the magnesium to agglomerate so that it can be drawn off. In selecting a flux attention must be given to any chemical reaction which might take place between the flux and the other constituents of the bath. One of the advantages obtained from the .electrolysis of these salts is that the nascent chlorin combines with the sulfid so as to form sulfur chlorid which does not attack the containing vessel and electrode or the metal formed in the process (as is the case where nascent chlorin is given off in other processes) though when the bath is almost depleted of magnesium sulfid or is maintained at too high a temperature some chlorin in the free state with sulfur may be given 011". Another advantage is that the reaction is carried on with a less expenditure of electric current than hitherto in the electric production of metals. We have found that we get good results when working with about ei ht or ten volts in the bath.

The process is est carried on in a closed electrolytic vessel in which a current of nitrogen or other gas inert for the purpose is maintained. The process does not require a diaphragm in the bath but this may be used if desired. The electrodes may be of any suitable material which will not be attacked by the bath, graphite for example. Or one mightbe graphite and another iron. The temperature and current densities will vary considerably, according to the size. shape, &c., of the bath and electrodes.

Having thus described our invention what we claim as new and desire to secure by Letters Patent is 1. A process for preparing metallic magnesium which consists in electrolyzing a mixture of chlorid and sulfid of the metal in an electrolytic bath.

2. A process for preparing metallic magnesium which consists in fusing magnesium chlorid and then adding gradually magnesium sulfid to the fused salt and electrolyzing the bath.

3. A processfor preparing metallic magnesium which consists in electrolyzing a mixture of chlorid and sulfid of the metal in an electrolytic bath and then introducing into the bath a suitable flux which will cause the magnesium to agglomerate so that it can be drawn off, the said flux being inert with respect to the constituents of the bath.

In witness whereof we have signed our names to this specification in the presence of two subscribing witnesses.

O. J. WORTH, W. E. Rooms. 

